| Message ID | 20170131180915.GA16450@bhelgaas-glaptop.roam.corp.google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
Hi Bjorn, On Tue, Jan 31, 2017 at 7:09 PM, Bjorn Helgaas <helgaas@kernel.org> wrote: > On Tue, Jan 31, 2017 at 04:33:15PM +0100, Geert Uytterhoeven wrote: >> On Tue, Jan 31, 2017 at 4:10 PM, Bjorn Helgaas <bhelgaas@google.com> wrote: >> > A match in the rcar_pcie_of_match[] table is required, so check that first, >> > before we start setting up things that need to be undone if it fails. No >> > functional change intended. >> > >> > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> >> > --- >> > drivers/pci/host/pcie-rcar.c | 10 +++++----- >> > 1 file changed, 5 insertions(+), 5 deletions(-) >> > >> > diff --git a/drivers/pci/host/pcie-rcar.c b/drivers/pci/host/pcie-rcar.c >> > index 0d9b96c3c49d..c91ff0b91be8 100644 >> > --- a/drivers/pci/host/pcie-rcar.c >> > +++ b/drivers/pci/host/pcie-rcar.c >> > @@ -1129,6 +1129,10 @@ static int rcar_pcie_probe(struct platform_device *pdev) >> > int err; >> > int (*hw_init_fn)(struct rcar_pcie *); >> > >> > + of_id = of_match_device(rcar_pcie_of_match, dev); >> > + if (!of_id || !of_id->data) >> > + return -EINVAL; >> > + >> >> As this driver is DT-only, none of the above can fail, and you could just do >> >> hw_init_fn = of_device_get_match_data(dev); >> >> instead, getting rid of of_id completely. > > Oh, I really like that, thanks for pointing that out! > > I was about to say that I personally would not check of_id->data for NULL, > because it is only NULL if somebody adds an entry to rcar_pcie_of_match > without a .data member. In that case, I'd rather take the NULL pointer > dereference than return -EINVAL because it's too easy to ignore the > -EINVAL. > > What do you think about the following? Thanks, looks fine! > commit 25bd3aa972ee32f04590aa68b2b785dce36b036a > Author: Bjorn Helgaas <bhelgaas@google.com> > Date: Tue Jan 31 08:45:49 2017 -0600 > > PCI: rcar: Use of_device_get_match_data() to simplify probe > > This is a DT-only driver, so the only way to call rcar_pcie_probe() is to > match an entry in rcar_pcie_of_match[], so of_id cannot be NULL. > > Furthermore, of_id->data can only be NULL if an rcar_pcie_of_match[] entry > has a NULL .data member. That's a driver defect, and we don't want to > return -EINVAL, which is easy to ignore. We'd rather take the NULL pointer > dereference so we notice the problem and fix it. > > Use of_device_get_match_data() to retrieve the hw_init_fn pointer. No > functional change intended. > > Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org> > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On Tue, Jan 31, 2017 at 10:43:39PM +0100, Geert Uytterhoeven wrote: > Hi Bjorn, > > On Tue, Jan 31, 2017 at 7:09 PM, Bjorn Helgaas <helgaas@kernel.org> wrote: > > On Tue, Jan 31, 2017 at 04:33:15PM +0100, Geert Uytterhoeven wrote: > >> On Tue, Jan 31, 2017 at 4:10 PM, Bjorn Helgaas <bhelgaas@google.com> wrote: > >> > A match in the rcar_pcie_of_match[] table is required, so check that first, > >> > before we start setting up things that need to be undone if it fails. No > >> > functional change intended. > >> > > >> > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> > >> > --- > >> > drivers/pci/host/pcie-rcar.c | 10 +++++----- > >> > 1 file changed, 5 insertions(+), 5 deletions(-) > >> > > >> > diff --git a/drivers/pci/host/pcie-rcar.c b/drivers/pci/host/pcie-rcar.c > >> > index 0d9b96c3c49d..c91ff0b91be8 100644 > >> > --- a/drivers/pci/host/pcie-rcar.c > >> > +++ b/drivers/pci/host/pcie-rcar.c > >> > @@ -1129,6 +1129,10 @@ static int rcar_pcie_probe(struct platform_device *pdev) > >> > int err; > >> > int (*hw_init_fn)(struct rcar_pcie *); > >> > > >> > + of_id = of_match_device(rcar_pcie_of_match, dev); > >> > + if (!of_id || !of_id->data) > >> > + return -EINVAL; > >> > + > >> > >> As this driver is DT-only, none of the above can fail, and you could just do > >> > >> hw_init_fn = of_device_get_match_data(dev); > >> > >> instead, getting rid of of_id completely. > > > > Oh, I really like that, thanks for pointing that out! > > > > I was about to say that I personally would not check of_id->data for NULL, > > because it is only NULL if somebody adds an entry to rcar_pcie_of_match > > without a .data member. In that case, I'd rather take the NULL pointer > > dereference than return -EINVAL because it's too easy to ignore the > > -EINVAL. > > > > What do you think about the following? > > Thanks, looks fine! > > > commit 25bd3aa972ee32f04590aa68b2b785dce36b036a > > Author: Bjorn Helgaas <bhelgaas@google.com> > > Date: Tue Jan 31 08:45:49 2017 -0600 > > > > PCI: rcar: Use of_device_get_match_data() to simplify probe > > > > This is a DT-only driver, so the only way to call rcar_pcie_probe() is to > > match an entry in rcar_pcie_of_match[], so of_id cannot be NULL. > > > > Furthermore, of_id->data can only be NULL if an rcar_pcie_of_match[] entry > > has a NULL .data member. That's a driver defect, and we don't want to > > return -EINVAL, which is easy to ignore. We'd rather take the NULL pointer > > dereference so we notice the problem and fix it. > > > > Use of_device_get_match_data() to retrieve the hw_init_fn pointer. No > > functional change intended. > > > > Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org> > > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> > > Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Simon Horman <horms+renesas@verge.net.au>
diff --git a/drivers/pci/host/pcie-rcar.c b/drivers/pci/host/pcie-rcar.c index 0d9b96c3c49d..cb07c45c1858 100644 --- a/drivers/pci/host/pcie-rcar.c +++ b/drivers/pci/host/pcie-rcar.c @@ -1125,7 +1125,6 @@ static int rcar_pcie_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; struct rcar_pcie *pcie; unsigned int data; - const struct of_device_id *of_id; int err; int (*hw_init_fn)(struct rcar_pcie *); @@ -1149,11 +1148,6 @@ static int rcar_pcie_probe(struct platform_device *pdev) if (err) return err; - of_id = of_match_device(rcar_pcie_of_match, dev); - if (!of_id || !of_id->data) - return -EINVAL; - hw_init_fn = of_id->data; - pm_runtime_enable(dev); err = pm_runtime_get_sync(dev); if (err < 0) { @@ -1162,6 +1156,7 @@ static int rcar_pcie_probe(struct platform_device *pdev) } /* Failure to get a link might just be that no cards are inserted */ + hw_init_fn = of_device_get_match_data(dev); err = hw_init_fn(pcie); if (err) { dev_info(dev, "PCIe link down\n");